rangeTraits: A container of functions to apply on a `SpatialPolygons object`

Description

This is a convenience function returning a named list of functions.

Usage

rangeTraits(..., use.default)

Arguments

...

functions, given as myfun = FUN, to apply on a SpatialPolygons object

use.default

If TRUE, the default, the output list contains functions to extract Area, Median, Min and Max extent of the SpatialPolygons object. This option is ignored if no functions are given.

Value

Returns a named list containing extractor functions to apply on SpatialPolygons objects.

Details

The function returns a named list so any additional functions should be given as rangeTraits(funName1 = FUN1, funName2 = FUN2) where FUN1, FUN2 are SpatialPolygons extractor functions.

Examples

Run this code

summary(rangeTraits(use.default = F))

f = system.file(package = "rangeMapper", "extdata", "wrens", "vector")
troaed = selectShpFiles(f, ogr = TRUE, 
	polygons.only = TRUE)[71, ] # path to Troglodytes_aedon

r = readOGR(troaed$dsn, troaed$layer)

# Beware of the value returned for Area!
sapply(rangeTraits(), function(x) x(r) )

# Define an extra function to compute correct Area
Area2 = function(x) {
x = spTransform(x, 
CRS("+proj=cea +lon_0=0 +lat_ts=30 +x_0=0 +y_0=0 +ellps=WGS84 +units=m +no_defs") 
	)

sum(sapply(slot(x, "polygons"), function(x) slot(x, "area") ))
}

sapply(rangeTraits(Area_sqm = Area2), function(x) x(r) )